Up to now in Japan when treating carcasses of slaughtered animals such as cattle, pigs, etc., operation processes of Knocking (butchering)—bloodletting—foots/corners cutting—pretreatment—skinning—cleaning—breast cutting—head cutting off—bowels removing—halving along backbone—inspection of dressed carcass—trimming—cleaning for sterilization are carried out sequentially on a processing line in a slaughterhouse, and in overseas operation processes excluding the cleaning process from the processes mentioned above are carried out sequentially on a processing line in a slaughterhouse.
Dressed carcasses processed like this are carried to a refrigerator for storage and supplied for human consumption after a considerable circulation period of time.
Temperature rises to near 40° C. in the core of a dressed carcass processed in a conventional processing line due to activity of the enzymes in the meat. Therefore, it is needed to lower the temperature of the dressed carcass as far as possible before it is carried into a refrigerator for storage. Conventionally, inner part temperature has been lowered to about 7° C. in 12˜24 hours by temporal storage in a refrigerator, then severed to be shipped.
With a conventional cooling method like this, it takes a long period of time for cooling the dressed carcass and freshness is lost.
In patent literature 1 (JP-A-2001-61403) is disclosed an art with which, by blasting cold air on the surface of a dressed carcass at high speed in the processing line, heat and water is removed quickly from the surface thereof to enhance decrease in temperature of the dressed carcass processed as mentioned above, to suppress adhesion of microbes on the surface, and to preserve freshness thereof. However, with the art of patent literature 1, absolute humidity is low within the refrigerator as it is usually cooled to about 5° C., so when the carcass is carried in, ambient air around the carcass is heated by the heat of the carcass and relative humidity decreases. Therefore, water evaporates from the surface of the dressed carcass during cooling process, as a result process yield decreases by 2% or a little more.
In patent literature 2 (WO 03/099028 A1) is disclosed an art with which the cooling period of time is reduced, reduction in process yield is suppressed to 0.7˜1.0%, and the quality of the meat is enhanced, by cooling with cold air and spraying cold water while transferring dressed carcasses in a hanged attitude in a tunnel.
However, with the art disclosed in patent literature 2, there is a problem that the moisture sprayed from the atomizer 6 in the tunnel 1 splashes on every side and adheres to the wall of the cooling tunnel or to the cooler for generating cold air. Adhesion of moisture to the wall of the cooling tunnel deteriorates sanitary environment. Adhesion of moisture to the evaporator, etc. of the cooler causes freezing of water thereon, which results in reduced heat transfer, as a result, defrosting operation will be frequently needed and additional power will be consumed.
Further, there is a problem that; when a good amount of moisture adheres locally, the local area sucks excessive water and bloats out, changes in color to white or becomes soft and deteriorated in quality, and there will occur meat juice dripping together with water when the dressed carcass is cut on the cutting line.